Various data communication system require amplification of the information signal. Typically, the information data stream is created or provided in a digital format and is converted to an analog signal. The analog signal is then provided as an input to a high-power amplifier. The amplifier distorts the signal.
One method of correcting the distorting effect of the amplifier is to pre-distort the signal prior to supplying the signal as an input to the amplifier. In order to pre-distort the signal, the output of the amplifier is sampled to determine whether the pre-distortion of the signal accurately compensates for the distorting effect of the amplifier and, if necessary, to adjust the pre-distortion in order to improve the compensation. A feedback line is coupled off from the amplifier out for carrying a sample along a feedback path.
At the end of the feedback path is a device for making the determinations and adjustments regarding the pre-distortion. The determination/adjustment device operates is a digital format. Accordingly, the feedback sample signal is converted from an analog format (as occurs at the output of the amplifier) to a digital format. An analog-to-digital converter is located along the feedback path to accomplish the conversion. The analog-to-digital converter must have a sufficiently large bandwidth and dynamic range to accommodate the signal input to the analog-to-digital converter such that data is not lost.